The invention relates to a multicomponent yarn, comprising as one component an open end yarn core formed from staple fibers and a component forming a longitudinal formation from silk, yarn and the like and a method of and apparatus for the manufacture of such yarn.
The manufacture of a two-component yarn directly in a spinning rotor chamber is, for instance, disclosed in U.S. Pat. No. 3,445,993, in which on a yarn core, in the course of its passage through the spinning chamber, there is wrapped staple yarn, which has been formed in the spinning chamber in the section thereof between the entrance into the yarn withdrawal channel and the yarn withdrawing rollers. The speed of feeding the yarn core into the spinning rotor is determined by the withdrawing speed of the rollers which withdraw the yarn. The yarn core is stored on a freely rotatable countershaft bobbin, which is arranged so as to secure a constant pull and winding off of the yarn core; the latter passes over a brake situated below the countershaft bobbin. The formation of different kinds of two component, that is, of core yarns, is also disclosed in French Pat. No. 1,567,718, in which the yarn core is introduced into the spinning rotor onto the collecting surface on fibers deposited thereon or in the close neighborhood of this collecting surface, where both components, i.e. the yarn core and the fibers deposited on the collecting surface, are connected by twisting and thus form a single yarn, whereby the yarn core due to contact with the collecting surface is given a false twist. By this mutual twisting the yarn core is shortened, and in consequence thereof the withdrawing speed of the resulting yarn is always adjusted to be somewhat lower than the feeding speed of the yarn core.
A similar method and apparatus for forming a core yarn is described in Swiss Pat. No. 585,284. A drawback of these known methods and arrangements is that only a limited variety of core yarns can be obtained the properties of which can be altered by changing the withdrawing speed of the core yarn. This withdrawing speed, however, cannot be altered at will as it is always necessary to observe conditions for folding up the fibers from the collecting surface to form the final yarn.
It is known that a stronger and more uniform yarn is obtained by twisting two or more yarns together. The direction and number of twists influence the properties of twisted yarns. In the case of yarns twisted in direction z+z/Z, s+s/S with a normal number of twists, a hard and coarse yarn is obtained. When using twists z+s/S Z+s/Z one of them is twisted, and the other is untwisted. The manufacture of different yarns designed for a visual effect is known, and, in addition to core yarns, spiral yarns are also made, such spiral yarns usually comprising one or more fundamental yarns, one or more yarns for visual effect, and further crossing yarns. The thus composed yarn is manufactured by double twisting. By the preliminary twist a preliminary yarn is prepared--the fundamental yarn is twisted together with the effective yarn, whereby both yarns are disposed at a certain mutual angle with respect to their axis; in the second twisting the preliminary yarn is twisted together with one crossing yarn in a counter-direction. The twisting direction is chosen in the second twisting so that in the course of fixing or crossing, the fundamental yarn is additionally twisted and the effective yarn is untwisted. From this review, it is obvious that the manufacture of multi-component yarns requires a considerable amount of labor and is costly, and that the individual yarns in the course of twisting change their character.